Those familiar with hydrocarbon conversion processes have long recognized that it would be advantageous to perform the processes in a continuous manner. This has prompted the development of moving bed catalytic processes. In these processes, the catalyst descends through a reaction zone in a compact, nonfluidized bed due to the action of gravity. That is, as catalyst is gradually removed from the bottom of the reaction zone, regenerated catalyst fed to the top of the reactor gradually moves downward to fill in the now available void spaces thereby providing a continuous bed of catalyst which is periodically changed. An early example of this type of reactor flow is provided in FIG. 3 of U.S. Pat. No. 2,303,717 issued to M. H. Arveson. This particular patent teaches the use of a moving bed reaction zone and a moving bed regeneration zone, the use of lockhoppers and stripping zones in catalyst treatment and transportation systems and the use of a conveying gas to lift catalyst from the bottom of the apparatus to the top of the apparatus. Another example of a moving bed hydrocarbon conversion process is presented in U.S. Pat. No. 3,238,122 issued to W. A. Hagerbaumer.
U.S. Pat. No. 3,725,249 issued to K. D. Vesely et al is pertinent for its teaching of a moving bed reforming operation with associated regeneration equipment. This reference is pertinent as the preferred embodiment of the subject invention is usage upon such a moving bed reforming operation. This reference is also pertinent for its overall teaching in regard to the use of lift engaging vessels to transport the catalyst, lockhoppers, and other catalyst handling techniques. U.S. Pat. No. 3,978,150 issued to F. G. McWilliams, Jr. is pertinent for its showing of a continuous or moving bed dehydrogenation process which employs similar catalyst transfer techniques including the utilization of a catalyst reducing zone as part of the regeneration procedure.
The above-cited references teach the use of nitrogen and methane to fluidize and transport catalyst upward from lift engaging vessels. The use of hydrogen to transport catalyst within such a moving bed process is also known as is shown by FIG. 1 of the article appearing at page 98 of the May, 1973 edition of Hydrocarbon Processing. U.S. Pat. No. 3,839,196 issued to the applicant indicates hydrogen used for such catalyst transport can be recycle gas recovered by separation from the effluent stream of the reaction zone.
It is believed that heretofore the gas stream employed in the lockhoppers and treating zones has been derived from gas supplied to the overall process from an outside source or from gas recovered at a point downstream from the reaction zone and then recycled or returned to the process. It is also believed that heretofore no attempt has been made to employ the products separator of the process as the receptacle of used auxiliary gas streams or to segregate various gases fed to the products separator.